Core: 4. Transitions#
This tutorial shows settings for transitions between flows and nodes.
Here, conditions for transition between many different script steps are shown.
Some of the destination steps can be set using labels.
First of all, let’s do all the necessary imports from DFF.
[1]:
# installing dependencies
%pip install -q dff
Note: you may need to restart the kernel to use updated packages.
[2]:
import re
from dff.script import TRANSITIONS, RESPONSE, Context, NodeLabel3Type, Message
import dff.script.conditions as cnd
import dff.script.labels as lbl
from dff.pipeline import Pipeline
from dff.utils.testing.common import (
check_happy_path,
is_interactive_mode,
run_interactive_mode,
)
Let’s define the functions with a special type of return value:
NodeLabel3Type == tuple[str, str, float]
which means that transition returns a tuple with flow name, node name and priority.
[3]:
def greeting_flow_n2_transition(_: Context, __: Pipeline) -> NodeLabel3Type:
return ("greeting_flow", "node2", 1.0)
def high_priority_node_transition(flow_label, label):
def transition(_: Context, __: Pipeline) -> NodeLabel3Type:
return (flow_label, label, 2.0)
return transition
Priority is needed to select a condition in the situation where more than one condition is True. All conditions in TRANSITIONS are being checked. Of the set of True conditions, the one that has the highest priority will be executed. Of the set of True conditions with largest priority the first met condition will be executed.
Out of the box dff.script.core.labels offers the following methods:
lbl.repeat()returns transition handler which returnsNodeLabelTypeto the last node,lbl.previous()returns transition handler which returnsNodeLabelTypeto the previous node,lbl.to_start()returns transition handler which returnsNodeLabelTypeto the start node,lbl.to_fallback()returns transition handler which returnsNodeLabelTypeto the fallback node,lbl.forward()returns transition handler which returnsNodeLabelTypeto the forward node,lbl.backward()returns transition handler which returnsNodeLabelTypeto the backward node.
There are three flows here: global_flow, greeting_flow, music_flow.
[4]:
toy_script = {
"global_flow": {
"start_node": { # This is an initial node,
# it doesn't need a `RESPONSE`.
RESPONSE: Message(),
TRANSITIONS: {
("music_flow", "node1"): cnd.regexp(
r"talk about music"
), # first check
("greeting_flow", "node1"): cnd.regexp(
r"hi|hello", re.IGNORECASE
), # second check
"fallback_node": cnd.true(), # third check
# "fallback_node" is equivalent to
# ("global_flow", "fallback_node").
},
},
"fallback_node": { # We get to this node if
# an error occurred while the agent was running.
RESPONSE: Message("Ooops"),
TRANSITIONS: {
("music_flow", "node1"): cnd.regexp(
r"talk about music"
), # first check
("greeting_flow", "node1"): cnd.regexp(
r"hi|hello", re.IGNORECASE
), # second check
lbl.previous(): cnd.regexp(
r"previous", re.IGNORECASE
), # third check
# lbl.previous() is equivalent
# to ("previous_flow", "previous_node")
lbl.repeat(): cnd.true(), # fourth check
# lbl.repeat() is equivalent to ("global_flow", "fallback_node")
},
},
},
"greeting_flow": {
"node1": {
RESPONSE: Message("Hi, how are you?"),
# When the agent goes to node1, we return "Hi, how are you?"
TRANSITIONS: {
(
"global_flow",
"fallback_node",
0.1,
): cnd.true(), # second check
"node2": cnd.regexp(r"how are you"), # first check
# "node2" is equivalent to ("greeting_flow", "node2", 1.0)
},
},
"node2": {
RESPONSE: Message("Good. What do you want to talk about?"),
TRANSITIONS: {
lbl.to_fallback(0.1): cnd.true(), # third check
# lbl.to_fallback(0.1) is equivalent
# to ("global_flow", "fallback_node", 0.1)
lbl.forward(0.5): cnd.regexp(r"talk about"), # second check
# lbl.forward(0.5) is equivalent
# to ("greeting_flow", "node3", 0.5)
("music_flow", "node1"): cnd.regexp(
r"talk about music"
), # first check
# ("music_flow", "node1") is equivalent
# to ("music_flow", "node1", 1.0)
lbl.previous(): cnd.regexp(
r"previous", re.IGNORECASE
), # third check
},
},
"node3": {
RESPONSE: Message("Sorry, I can not talk about that now."),
TRANSITIONS: {lbl.forward(): cnd.regexp(r"bye")},
},
"node4": {
RESPONSE: Message("Bye"),
TRANSITIONS: {
"node1": cnd.regexp(r"hi|hello", re.IGNORECASE), # first check
lbl.to_fallback(): cnd.true(), # second check
},
},
},
"music_flow": {
"node1": {
RESPONSE: Message(
text="I love `System of a Down` group, "
"would you like to talk about it?"
),
TRANSITIONS: {
lbl.forward(): cnd.regexp(r"yes|yep|ok", re.IGNORECASE),
lbl.to_fallback(): cnd.true(),
},
},
"node2": {
RESPONSE: Message(
text="System of a Down is "
"an Armenian-American heavy metal band formed in 1994."
),
TRANSITIONS: {
lbl.forward(): cnd.regexp(r"next", re.IGNORECASE),
lbl.repeat(): cnd.regexp(r"repeat", re.IGNORECASE),
lbl.to_fallback(): cnd.true(),
},
},
"node3": {
RESPONSE: Message(
text="The band achieved commercial success "
"with the release of five studio albums."
),
TRANSITIONS: {
lbl.forward(): cnd.regexp(r"next", re.IGNORECASE),
lbl.backward(): cnd.regexp(r"back", re.IGNORECASE),
lbl.repeat(): cnd.regexp(r"repeat", re.IGNORECASE),
lbl.to_fallback(): cnd.true(),
},
},
"node4": {
RESPONSE: Message("That's all what I know."),
TRANSITIONS: {
greeting_flow_n2_transition: cnd.regexp(
r"next", re.IGNORECASE
), # second check
high_priority_node_transition(
"greeting_flow", "node4"
): cnd.regexp(
r"next time", re.IGNORECASE
), # first check
lbl.to_fallback(): cnd.true(), # third check
},
},
},
}
# testing
happy_path = (
(Message("hi"), Message("Hi, how are you?")),
(
Message("i'm fine, how are you?"),
Message("Good. What do you want to talk about?"),
),
(
Message("talk about music."),
Message(
text="I love `System of a Down` group, "
"would you like to talk about it?"
),
),
(
Message("yes"),
Message(
text="System of a Down is "
"an Armenian-American heavy metal band formed in 1994."
),
),
(
Message("next"),
Message(
text="The band achieved commercial success "
"with the release of five studio albums."
),
),
(
Message("back"),
Message(
text="System of a Down is "
"an Armenian-American heavy metal band formed in 1994."
),
),
(
Message("repeat"),
Message(
text="System of a Down is "
"an Armenian-American heavy metal band formed in 1994."
),
),
(
Message("next"),
Message(
text="The band achieved commercial success "
"with the release of five studio albums."
),
),
(Message("next"), Message("That's all what I know.")),
(
Message("next"),
Message("Good. What do you want to talk about?"),
),
(Message("previous"), Message("That's all what I know.")),
(Message("next time"), Message("Bye")),
(Message("stop"), Message("Ooops")),
(Message("previous"), Message("Bye")),
(Message("stop"), Message("Ooops")),
(Message("nope"), Message("Ooops")),
(Message("hi"), Message("Hi, how are you?")),
(Message("stop"), Message("Ooops")),
(Message("previous"), Message("Hi, how are you?")),
(
Message("i'm fine, how are you?"),
Message("Good. What do you want to talk about?"),
),
(
Message("let's talk about something."),
Message("Sorry, I can not talk about that now."),
),
(Message("Ok, goodbye."), Message("Bye")),
)
[5]:
pipeline = Pipeline.from_script(
toy_script,
start_label=("global_flow", "start_node"),
fallback_label=("global_flow", "fallback_node"),
)
if __name__ == "__main__":
check_happy_path(pipeline, happy_path)
if is_interactive_mode():
run_interactive_mode(pipeline)
(user) >>> text='hi'
(bot) <<< text='Hi, how are you?'
(user) >>> text='i'm fine, how are you?'
(bot) <<< text='Good. What do you want to talk about?'
(user) >>> text='talk about music.'
(bot) <<< text='I love `System of a Down` group, would you like to talk about it?'
(user) >>> text='yes'
(bot) <<< text='System of a Down is an Armenian-American heavy metal band formed in 1994.'
(user) >>> text='next'
(bot) <<< text='The band achieved commercial success with the release of five studio albums.'
(user) >>> text='back'
(bot) <<< text='System of a Down is an Armenian-American heavy metal band formed in 1994.'
(user) >>> text='repeat'
(bot) <<< text='System of a Down is an Armenian-American heavy metal band formed in 1994.'
(user) >>> text='next'
(bot) <<< text='The band achieved commercial success with the release of five studio albums.'
(user) >>> text='next'
(bot) <<< text='That's all what I know.'
(user) >>> text='next'
(bot) <<< text='Good. What do you want to talk about?'
(user) >>> text='previous'
(bot) <<< text='That's all what I know.'
(user) >>> text='next time'
(bot) <<< text='Bye'
(user) >>> text='stop'
(bot) <<< text='Ooops'
(user) >>> text='previous'
(bot) <<< text='Bye'
(user) >>> text='stop'
(bot) <<< text='Ooops'
(user) >>> text='nope'
(bot) <<< text='Ooops'
(user) >>> text='hi'
(bot) <<< text='Hi, how are you?'
(user) >>> text='stop'
(bot) <<< text='Ooops'
(user) >>> text='previous'
(bot) <<< text='Hi, how are you?'
(user) >>> text='i'm fine, how are you?'
(bot) <<< text='Good. What do you want to talk about?'
(user) >>> text='let's talk about something.'
(bot) <<< text='Sorry, I can not talk about that now.'
(user) >>> text='Ok, goodbye.'
(bot) <<< text='Bye'